Engines and other machines usually include an oil filler tube to check and modify the oil volume within an oil tank. In the case of aircraft engines, the oil tank is pressurized and loss of oil during flight leads to rapid overheating of the bearings and catastrophic engine failure. In the event that the oil filler tube cap has been improperly placed or omitted altogether, oil filler tubes include a ball valve to impede oil leakage.
U.S. Pat. No. 1,756,976 to Ehlers shows a float ball valve to prevent escape of oil. Another example is shown in U.S. Statutory Invention Registration No. H438 to Viksne et al. which includes a float ball valve to prevent overflow of fuel through a fuel sounding tube.
An acknowledged problem with ball valves is that the float ball often sticks to the valve seat after operation of the engine particularly when the oil tank is pressurized and the float ball is forced by pressure into engagement with the valve seat. The relatively light weight ball of the valve can be stuck to the valve seat due to the viscosity of the oil, surface tension of oil, a vacuum state may be created that maintains the ball in place or the ball may be slightly distorted due to the pressure applied to it during engine operation. The blockage of the filler tube by the float ball stuck to the valve seat creates difficulty in adding oil to the tank through the filler tube and may give the false impression that the oil tank is full once oil is poured into the blocked filler tube.
It is an object of the invention to provide an oil filler cap that include a device to automatically prevent sticking of the ball within the ball valve and eliminate the potential for human error in judging the volume of oil within the engine.
Further objects of the invention will be apparent from review of the disclosure, drawings and description of the invention below.